Salesforce Senior Technical Support Engineer Interview Questions and Answers

Find sum of squares of numbers in list using stream API.

• Use mapToInt() to convert list of integers to IntStream

• Use map() to square each element of IntStream

• Use sum() to get the sum of squares

Searching in 2D sorted array row wise and column wise.

• Start from the top right corner or bottom left corner

• Compare the target with the current element

• Move left or down if target is smaller or move right or up if target is larger

• Repeat until target is found or out of bounds

Use Dijkstra's algorithm to find the shortest path between 2 vertices in a graph.

• Implement Dijkstra's algorithm to find the shortest path

• Create a priority queue to keep track of the vertices with the shortest distance

• Use a visited set to avoid revisiting vertices

• Stop when the destination vertex is reached

• Return the shortest path found

• Example: finding the shortest path between A and D in a graph with weighted edges: A->...read more

Find pairs in an array with sum equal to 0.

• Use a hash table to store the frequency of each element.

• Iterate through the array and for each element, check if its complement (negative value) exists in the hash table.

• If it exists, add the frequency of the complement to the count of pairs.

• Return the count of pairs.

• Example: array = [2, -2, 3, 0, -3], pairs = 2 (-2, 2 and -3, 3)

Design a traffic signal system

• Identify the number of lanes and intersections

• Determine the traffic flow and peak hours

• Choose appropriate sensors and controllers

• Implement a synchronization algorithm

• Consider emergency vehicle prioritization

• Include pedestrian crossing signals

• Ensure compliance with local regulations

Hashmap is a data structure that stores key-value pairs and provides constant time complexity for insertion, deletion, and retrieval.

• Hashmap uses hashing function to map keys to indices in an array

• Collisions can occur when multiple keys map to the same index, which can be resolved using separate chaining or open addressing

• Java implementation: HashMap map = new HashMap<>();

Printing patterns using code

• Identify the pattern to be printed

• Use loops to print the pattern

• Adjust the loop variables to control the pattern

• Use conditional statements to modify the pattern

• Examples: printing stars, triangles, squares, etc.

Common point in linked list refers to the node where two or more linked lists intersect.

• The common point can be found by traversing both linked lists and comparing the nodes.

• The common point can also be found by using two pointers, one for each linked list, and moving them until they meet at the common point.

• Examples include finding the intersection point of two linked lists or finding the loop in a linked list.